摘要：本文介绍了氧化镁轻烧与电熔绿色智能制造工艺的创新，包括轻烧氧化镁的二氧化碳全回收工艺、氧化镁轻烧与大结晶电熔联合生产工艺、大结晶氧化镁自动化智能化清洁生产工艺，以及相关产品的特点。这些工艺具有节能减排、环保安全、高效智能等优点，对氧化镁行业可持续发展具有重要的方向启发。
关键词：氧化镁；轻烧氧化镁；二氧化碳回收；电熔氧化镁；大结晶氧化镁；清洁生产；智能制造

Abstract: This paper introduces the innovation of green intelligent manufacturing process for light-burned magnesia and fused magnesia, including full carbon dioxide recovery process of light-burned magnesia, combined production process of light-burned magnesia and fused magnesia, automatic intelligent cleaner production process of large crystalline fused magnesia, and the characteristics of related products. These processes have the advantages of energy saving and emission reduction, environmental protection and safety, high efficiency and intelligence, and may consolidate the technological foundation for the sustainable development of magnesium oxide industry.

Key words: MgO; light-burned magnesia; carbon dioxide recovery; fusion magnesia; large crystalline magnesia; cleaner production; intelligent manufacturing

轻烧氧化镁广泛地应用于冶金、化工、建材等工业，是钢铁工业不可替代的辅助材料。然而轻烧氧化镁生产是高污染、高能耗行业，传统的生产过程中会产生大量的CO2、NOx、SO2、CO等有害物质，污染大气。
轻烧氧化镁是制备大结晶电熔镁砂的原料，生产过程是将轻烧氧化镁成品投入到矿热炉中进行冶炼，一般需要加热至2800℃以上，冶炼结束后，炉筒在车间内自然冷却降温，最终得到大结晶电熔镁砂产品。一般称之为“二步法”工艺，即先生产轻烧氧化镁，再制得大结晶电熔镁砂，然而在这两个过程中轻烧窑炉与电熔矿热炉的独立生产运行中分别存在严重的能源浪费与消耗。
而目前生产大结晶电熔镁砂用矿热炉生产工艺落后，矿热炉装备简陋，自动化程度低，工人劳动强度高，生产过程中除尘效率低，工人工作环境恶劣，易引发淌炉事故，存在严重的人身安全隐患。
基于以上轻烧氧化镁、电熔氧化镁生产过程中碳排放、能源浪费、工艺落后等问题，本企业提出了绿色智能制造工艺，主要包括轻烧氧化镁的二氧化碳全回收工艺、氧化镁轻烧与大结晶电熔联合生产工艺、大结晶氧化镁自动化智能化清洁生产工艺。

1  轻烧氧化镁的二氧化碳全回收工艺方案
1.1 工艺系统
使用电能加热二氧化碳，并以二氧化碳作为传热介质加热分解菱镁矿，分解出的二氧化碳全回收，用于生产液态二氧化碳或干冰等产品，全过程无空气介入，不使用天然矿物燃料，从源头杜绝了有害污染物问题，真正实现温室气体与污染物零排放。

该工艺系统的核心目标是实现二氧化碳的全回收，彻底解决碳排放问题。具体过程为使用电能加热二氧化碳，并以二氧化碳作为传热介质加热分解菱镁矿。在整个过程中，分解出的二氧化碳会被全部回收，用于生产液态二氧化碳或干冰等二氧化碳产品。

1 CO2 recovery process of light-burned magnesia
1.1 Process system
This system uses electric energy to heat CO2, which is used as a transfer medium to heat magnesite. The decomposed CO2 is fully recovered for the production of liquid CO2 or dry ice and other products, the whole process has no air intervention, does not use natural fossil fuels, and eliminates harmful pollutants from the source, truly realizing zero emissions of greenhouse gases and pollutants.
The core goal of the process system is to achieve full recovery of CO2 and completely solve the problem of carbon emission. The specific process is to use electric energy to heat CO2, and use CO2 as a heat transfer medium to heat and decompose magnesite. During the entire process, the decomposed CO2 is fully recovered and used to produce CO2 products such as liquid CO2 or dry ice.

1.2 工艺流程
（1）原料预热与轻烧：菱镁矿原料进入轻烧窑炉，与高温二氧化碳对流换热，原料分解为成品氧化镁和二氧化碳，新分解产生的二氧化碳以及轻烧换热后的高温二氧化碳上行进入炉窑预热器预热原料，降温的二氧化碳经过除尘器过滤处理后送入二氧化碳缓冲罐。
（2）成品冷却：轻烧窑炉将热态轻烧氧化镁排出到沸腾冷却器，用来自二氧化碳缓冲罐的低温二氧化碳换热降温，还可导入液态二氧化碳或干冰强化冷却。
（3）产品收集：来自沸腾冷却器的二氧化碳与轻烧氧化镁在旋风集料器中分离，氧化镁从下部输出成为产品，二氧化碳气体从上部排出进入电磁感应加热炉，继续循环。
（4）二氧化碳加热：电磁感应加热炉将二氧化碳气体加热成高温二氧化碳（不高于 1200℃），并送入轻烧炉窑。

1.2 Technological process
(1) Preheating and light-burning of raw materials: Magnesite is put into the the light-burned furnace, convective heat exchange with high temperature CO2, the raw materials are decomposed into MgO and CO2. The CO2 generated by the new decomposition and the high-temperature CO2 after the heat exchange enter the furnace preheater to preheat the raw material, and the cooled CO2 is filtered by the dust collector and sent to the CO2 buffer tank.
(2) Product cooling: The light-burned furnace will discharge the hot MgO into the boiling cooler, where the low-temperature CO2 from the CO2 buffer tank is conducted to cool down the powder, here if necessary liquid CO2 or dry ice can be used to enhance cooling.
(3) Product collection: The light-burned CCM is then separated from the cyclone collector, and be outlet from the lower part into the product silo. The CO2 gas is discharged from the upper part into the electromagnetic induction furnace to be heated and get into the continuous cycle.
(4) CO2 heating: The electromagnetic induction furnace heats the CO2 (not higher than 1200 °C) and sends it to the light-burned furnace.

1.3 工艺特点
（1）节能环保：全过程无空气介入，不使用天然矿物燃料，因此无需投资和运行脱硫与脱硝设备。这从源头杜绝了传统工艺采用矿物质燃料轻烧菱镁石时产生SO2和NOX有害污染物的问题。
（2）单一气体成分：过程气体成分为单一的二氧化碳，可高效实现二氧化碳全回收，真正实现温室气体与污染物零排放。

1.4 二氧化碳全回收工艺方案的优势
（1）彻底解决碳排放问题：分解出的二氧化碳全回收，用于生产液态二氧化碳或干冰等产品，实现了温室气体零排放。
（2）节能环保：全过程无空气介入，不使用天然矿物燃料，从源头杜绝了传统工艺产生SO2和NOX有害污染物的问题，无需投资和运行脱硫与脱硝设备，减少了能源消耗和环境污染。
（3）高效回收二氧化碳：过程气体成分为单一的二氧化碳，可高效实现二氧化碳全回收。
（4）工艺创新：采用了新颖的工艺系统，使用电能加热二氧化碳并作为传热介质，具有创新性和前瞻性。

2  氧化镁轻烧与大结晶电熔联合生产工艺
2.1 工艺流程
（1）原料预热：通过提升机将小颗粒与粉状的菱镁矿运送到预热炉上部投料，在预热炉中进行预热。
（2）沸腾轻烧：预热的原料进入缓冲仓并投入到沸腾炉，进行流化床悬浮轻烧，形成热态轻烧粉。
（3）热粉收集：热态轻烧粉随热态烟气进入多级沉降室，通过重力作用自然沉降后，从底部传输到热粉缓冲仓，热态烟气从上部输出到预热炉。
（4）电熔生产：热粉缓冲仓中的热态轻烧粉输送到电熔炉，制备大结晶电熔镁砂。

1.3 Process Characteristics
(1) Energy conservation and environmental protection: The whole process is carried out without air involvement and does not use natural mineral fuels, thus eliminating the need for investment in and operation of desulfurization and denitrification equipment. This fundamentally eliminates the emission of harmful pollutants such as SO2 and NOx generated during the light calcination of magnesite using mineral fuels in traditional processes.
(2) Single gas composition: The process gas consists of pure carbon dioxide, enabling efficient full recovery of CO2 and truly achieving zero emissions of greenhouse gases and pollutants.

1.4 The advantages of CO2 recovery process solutions
(1) To solve the problem of carbon emissions: The decomposed CO2 is easier to be fully collected and used to produce products such as liquid CO2 or dry ice, achieving zero greenhouse gas emissions.
(2) Energy conservation and environmental protection：There is no air intervention in the whole process and no natural fossil fuel is used, so there is no need to invest in and operate desulfurization and denitrification equipment. This eliminates the problem of SO2 and NOX harmful pollutants from the traditional process of using mineral fuels to produce light-burned CCM.
(3) Efficient CO2 recovery: The outlet gas composition is a single CO2, which insures the  efficiency of full CO2 collection.
(4) Process innovation: To use electrical energy to heat CO2 and as a heat transfer medium is an innovative and forward-looking process system for producing light-burned CCM.

2 Combined production process of light-burned magnesia and fused magnesia
2.1 Technological process
(1) Preheating of raw materials: By a hoist, small particles and powdered magnesite is elevated up and feed into the preheating furnace to be heated.
(2) Light-burned CCM: The preheated magnesite goes to the buffer chamber and be conducted into the boiling furnace for fluid bed suspension light burning, forming hot CCM powder.
(3) Hot CCM powder collection: The hot CCM powder enters the multistage settling chamber with the hot flue gas, and after natural gravity settling, the hot powder is then conducted to the hot CCM powder buffer chamber, and the hot flue gas is output from the upper outlet to the preheating furnace.
(4) Electric fusion to produce LFM: The hot CCM powder in the buffer chamber is conducted directly into the submerged arc furnace to be fused to produce large crystalline fuse magnesia LFM.

2.2 技术意义
（1）解决能源浪费与消耗问题：该联合生产工艺将两个原本相对独立的生产过程进行了有效衔接，充分利用了高温轻烧氧化镁粉的物理热能，避免了热粉冷却能源浪费。
（2）设备优势：涉及的窑炉与装备占地面积小、成本低、能耗小，易于实现与操作，适合应用与推广。
综上所述，氧化镁轻烧与大结晶电熔联合生产工艺通过优化生产流程，实现了资源的高效利用和节能减排，具有重要的实际应用价值。

3  大结晶氧化镁自动化智能化清洁生产工艺
3.1自动化远程操控

大结晶氧化镁自动化智能化清洁生产工艺，实现了环保、安全、轻松、高效率、高产出、低能耗、低消耗的技术经济效果。具体包括增加炉盖封闭式除尘，现场无烟尘；控制与操作表房远离车间进入办公楼，操作环境安全舒适；冶炼电流、电压、给料、排气操作皆程序化自动化智能化，劳动强度大为改善；直接冶炼悬浮轻烧粉，无须压球破碎，减少工序，节能减排，降本增效；单炉产量高，优品98率高，产品体密确保3.0 g/cm3以上；全流程电耗低；原料利用率100%，除尘粉、落地灰、炉底料全部回炉利用。基本杜绝严重淌炉事故。

2.2 Technical significance
(1) Solving the problem of energy waste and consumption: The novel process well combines two relatively independent production processes together, makes full use of the thermal energy of the hot CCM powder, prevent the energy loss from hot CCM cooling process.
(2) Equipment advantages: The furnaces and equipment involved have the advantages of space saving, low cost, low energy consumption, easy realization and operation, and are suitable for application and promotion.

3 Automatic intelligent clean production process of LFM
3.1 Automated remote control

3.2 工艺特点
1、实现自动化远程操控：实现了对生产过程的自动化远程控制，提高了生产效率和精度。
2、环境有好：增加炉盖，封闭式除尘。使得电熔生产过程中现场无烟尘，有效减少了粉尘排放，对环境更加友好。
3、操控安全：（1）表房进入办公室，远离车间，操作环境更加安全，减少了事故发生的风险；（2）基本杜绝淌炉事故，不再经常浇水冷却，提高了炉工的安全保障。
4、劳动强度降低：（1）冶炼电流电压给料排气程序化自动化智能化，无需人工给料，劳动强度大大降低；（2）4台炉子只需2名表工，2台电脑，1名大炉工轻松巡视，对讲机通讯沟通，人员配置更加合理，工作效率提高；（3）红外监控，黑灯工厂，实现了智能化监控，减少了人工干预。
5、直接冶炼悬浮轻烧粉：直接冶炼悬浮轻烧粉，无须压球与破碎。减少工序，节能减排，降本增效，提高了生产效率。
6、高产出：（1）315KW变压器单炉产量平均10吨主产品；（2）足98% MgO优品率平均65%，国标LFM98AB产出率平均达到80%，产品质量优良，优品率和产出率较高。（3）足98% MgO产品体密确保3.0以上，产品密度达到较高标准。
7、低能耗：全流程电耗2300~2500度/主产品，能耗较低，有助于降低生产成本。
8、低消耗：（1）原料利用率100%，除尘粉、落地灰、炉底料全部回炉利用，减少了资源浪费，提高了原料利用率。（2）电极消耗平均15-17 kg/吨主产品，电极消耗较低，降低了生产成本。

3.3 产品提档

（1）微孔增韧型大结晶电熔镁砂：采用独特工艺与装备直接冶炼熔炼超细的浮选精矿粉的悬浮轻烧粉（200~300目），在高温电熔重结晶过程中，方镁石晶粒迅速长大，晶粒内出现大量微米级封闭气孔，并伴有部分晶界缝隙，能有效抵抗热应力，阻止裂纹扩散，起到晶内闭孔增韧的效果。

3.2 Process characteristics
1. Remote automatic control: The remote automatic control of the production process is realized, and the production efficiency and precision are improved.
2. Environment friendly: Added the furnace cover, closed dust removal. There is no smoke on site in the process of electric fusion, which effectively reduces dust emission and is more friendly to the environment.
3. Safety operation: (1) Control room moved into the office bldg., away from the workshop, the operating environment is safer. (2) Basically eliminate the furnace leaking accident, no longer frequent watering and cooling, improve the safety of the furnace workers.
4. Reduction of labor intensity: (1) Parameters like electric current and voltage, and feeding of CCM, electrode up and down are all programmed and operate automatically, no manual feeding of raw CCM powder, so the labor intensity is greatly reduced. (2) To operate the four furnaces, two ladies are siting in front of two computers in the air condition room, and one furnace site watcher with walkie-talkie is walking and supervising around in the workshop. (3) Infrared monitoring and black light factory. Realized intelligent monitoring and reduce manual intervention.
5. Directly fuse the suspension CCM powder: The suspension CCM powder is smelted directly, without pelleting and crushing. It reduces process step, saves energy and reduces emissions, reduces costs and increases efficiency, and improves production efficiency.
6. High output: (1) The average output of a single furnace equipped with a 315KW transformer is around 10 tons of main products. (2) Sufficient 98% MgO production ratio is average 65% or more, the national standard LFM98AB yield average of 80%. (3) Sufficient 98% MgO product density ensures 3.0g /cm3 or more, this guaranteed a high standard.
7. Low consumption of energy : The whole process power consumption of 2300~2500 degrees/ton main product, low energy consumption and low production costs.
8. Low consumption of raw materials: (1) The utilization rate of raw materials is 100%, and the dust removal powder, floor ash and bottom material are all reused, which reduces the waste of resources and improves the utilization rate of raw materials. (2) The average electrode consumption is 15-17 kg/ ton of the main product, and the electrode consumption is low, which reduces the production cost.

3.3 Product quality improvement
(1) The micro-pore toughened large crystalline fused magnesia（MT-LFM）: The special technology and equipment are used to directly smelt the suspension CCM powder (200~300 mesh). In the process of electric fusing and recrystallization at high temperature, the periclase grains grow rapidly, a large number of micron-level micro-pores are enclosed in the crystal, accompanied by some grain boundary gaps, which can effectively resist thermal stress, prevent crack diffusion, and toughen the crystal from the intracrystalline with these enclosed micron pores.

（2）超大结晶电熔镁砂：通过引入微量Cr2O3，活化晶格，促使晶体发育，结晶尺寸明显变大，达到2000μm~5000μm，约为普通大结晶镁砂晶粒尺寸的3倍。新产品具有晶粒间直接结合程度高、晶界杂质少的优点，晶体韧性大幅度提高，抗侵蚀性能明显优于一般大结晶产品。

(2)The ultra large crystalline fused magnesia（U-LFM）: By introducing trace amounts of Cr2O3, the crystal lattice is activated to promote crystal development. The size of large crystalline crystals significantly increases, reaching 2000μm ~ 5000μm, about 3 times the size of ordinary large crystalline magnesia. The new product has the advantages of high degree of direct intergrain bonding and less impurity in grain boundary, the crystal toughness is greatly improved, and the corrosion resistance is obviously better than that of general large crystalline products.

综上所述，大结晶氧化镁自动化智能化清洁生产工艺在环保、安全、劳动强度、生产效率、产品质量、能耗和原料利用等方面都具有明显优势，相比传统生产工艺更加先进和可持续。
4  总结
（1）轻烧氧化镁的二氧化碳全回收工艺，利用电能加热二氧化碳，并以二氧化碳作为传热介质加热分解菱镁矿，分解出的二氧化碳全回收，彻底解决碳排放问题。
（2）氧化镁轻烧与电熔绿色智能制造工艺，将电熔矿热炉和生产轻烧氧化镁的窑炉进行有效衔接与联合生产，解决了这两个过程中的能源浪费与消耗问题，实现节能减排。
（3）大结晶氧化镁自动化智能化清洁生产工艺，通过对矿热炉的炉盖系统、冷却装置、炉筒、防护系统等设备的改进，实现了高效化、自动化、清洁化生产。
联合荣大恒锐镁业位于辽宁省鞍山市岫岩满族自治县，有4台套独特工艺的电熔大结晶镁砂生产线，可年产微孔增韧大结晶与超大结晶电熔镁砂15000吨。

In summary, the automatic intelligent clean production process of LFM has obvious advantages in environmental protection, safety, labor intensity, production efficiency, product quality, energy consumption and raw material utilization, and is sustainable than the traditional production process.

4 Summary
(1)The CO2 recovery process of light-burned magnesia uses electric energy to heat CO2, and uses heated CO2 as a heat transfer medium to heat and decompose magnesite. The decomposed CO2 could be easier fully collected.
(2) The combined production process of light-burned magnesia and fused magnesiacan effectively connect and co-produce the electric melting furnace and the light-burned furnace, which solves the problem of energy waste and consumption in the two processes, and realizes energy saving and emission reduction.
(3) Through the improvement of the furnace cover system, cooling device, furnace barrel, protection system and other equipment, the automatic intelligent clean production process of LFM has realized high efficiency, automation and clean production.
Hengrui Magnesia (Allied Rongda Group) is located in Xiuyan Manchu Autonomous County, Anshan City, Liaoning Province. There are four sets of unique arc furnaces, which can produce 15000 tons of microporous toughened large crystalline fused magnesia and ultra large crystalline fused magnesia annually.